The invention relates to a supporting pillar for a body frame of a motor vehicle, in particular a passenger motor vehicle. The invention also relates to a method of construction or assembly for the supporting pillar.
A supporting pillar of this type is known from German Patent DE 40 16 730 C2. It has a pillar-shaped hollow body made of two profile shells which enclose a hollow space. A tubular body arranged in this hollow space extends longitudinally and is attached to the hollow body. In the known supporting pillar, the hollow body has an internal shell between two external profile shells. The contour of the internal shell is adapted to the shape of the tubular body. The tubular body is attached to the interior shell and the interior shell is used to attach the tubular body to the hollow shell.
The tubular body is usually made independently of the intermediate shell. Due to manufacturing differences which result in position differences, it is only possible to join these forms without any tension in exceptional cases. Since it is difficult to establish a connection under tension, the attachment can only be achieved at high cost.
Furthermore, assembly of the known supporting pillar is very expensive because the internal shell which is connected to the tubular body, has to be installed into the external shells.
If the supporting pillar is arranged near the seatback of a driver seat or front passenger seat (the so-called xe2x80x9cB-pillarxe2x80x9d), in modern passenger motor vehicles, there is required particularly good protection against lateral impact so that a side airbag located between the seatback and the supporting pillar may be properly deployed. The supporting pillar should be inclined as far as possible in relation to a vertical axis to create a flatter vehicle design.
It is the object of the present invention to provide a design for a supporting pillar which can be joined or assembled free of tension. Furthermore, it is an object that the supporting pillar is to ensure increased lateral impact protection.
For attachment purposes, the tubular body is first inserted into receiving apertures of bracket walls where the tubular body can be adjusted in the axial direction until it rests against the profile shell. The subsequent attachments between the tubular body and the bracket, and between the tubular body and the profile shell can then be made without any tension. Thus the invention makes it possible to compensate for differences and simplifies the production of the supporting pillar.
The lower region of the tubular body is inserted into the receiving apertures of the walls. These walls are essentially aligned perpendicular to the longitudinal direction of the tube. During a lateral impact, these walls are essentially parallel to the forces acting upon the tubular body. As a result of this design, particularly large support forces can be transmitted via these walls. Moreover, since the two walls are spaced apart from each other, additional moments can be supported via the bracket. During lateral impact, these moments act upon the tubular body, trying to turn this body around a longitudinal axis of the vehicle. This results in a particularly good dimensional stability during lateral impact. Accordingly, when the supporting pillar is used as a B-pillar, it can provide adequate spacing between the B pillar and the seatback for a sufficiently long time to ensure deployment of a side air bag.
In regard to quality assurance, the support pillar has additional advantages because straight-line contours are particularly easy to check, for example by applying a straight edge. It is just as easy to check predetermined inclinations of straight-line contours by using angle measuring devices.
In a preferred embodiment, the diameter of at least one of the receiving apertures in the walls of the bracket is larger than the external diameter of the tubular body inserted therein. A connecting disc is placed onto the tubular body, having an internal diameter corresponding to the external diameter of the tubular body, and an external diameter exceeding the diameter of the receiving aperture. The connecting disc is attached to the tubular body and to the bracket. This design makes it possible to compensate for differences in the area of the respective receiving aperture, since the tubular body is attached to the bracket indirectly via the respective connecting disc. This design also makes it possible to compensate for dimensional differences which occur during the manufacture of the elbow in the tubular body.
The bracket is preferably a folded body which rests against, and is attached to the profile shell. These characteristics make for easy production of the bracket and enable the transmission of relatively large forces when the vehicle is struck laterally.
In an advantageous embodiment, the bracket is arranged in the region of a door hinge and is connected to a fitting element of the door hinge. This connection to the fitting element increases the stability of the bracket, improving the load transmission between the tubular body and the body frame in the event of a crash. At the same time, it also increases the stability of the door hinge.
In another advantageous embodiment, in an upper region associated with the vehicle roof, the tubular body can rest against one of the profile shells along a first straight line and can be attached to the profile shell. In a middle region situated between the upper region and the lower region, the tubular body rests against one of the profile shells along a second straight line and is attached to this profile shell. The first line extends so that it is inclined in relation to the second line and the tubular body between its upper region and its middle region has a second elbow. As a result of this measure, the supporting pillar can have a particularly large inclination in relation to a vertical axis and yet comprises the desired stability characteristics.
In a particular improvement of this embodiment, the tubular body can comprise two tubes. With this design, one of the two tubes is inserted into the other and are attached, with each of the tubes having a elbow on a middle region. This design makes it possible to compensate for position differences which have to be considered when making the two elbows and in the production of the respective profile shell, by displacing the two tubes in relation to each other accordingly. Thus, this design ensures a tension free joining of the pillar to the motor vehicle body.
To provide particularly good stability values for the supporting pillar, tubes made of a high-strength material and having a constant cross-section are used for producing the tubular body. High-strength tubes of this type are relatively simple to produce, thus making the supporting pillar according to the invention relatively cost-effective.
Advantageously, the tubular body rests along one of the lines at points against the profile shell. The tubular body thus rests in a punctiform way against this profile shell. This measure facilitates automatic production, in particular with welding equipment or welding robots.
The bracket may comprise two walls which are spaced apart from each other and which extend essentially parallel in relation to each other. Each of these walls have a receiving aperture in which this tubular body is inserted. The tubular body is attached to the bracket at the receiving apertures.
The present invention also includes a method for the construction of a supporting pillar. A tubular body is manufactured having at least one elbow and a profile shell is produced with a bracket attached inside.
The tubular body is inserted into the profile shell. The lower region of the tubular body enters the receiving apertures shaped in the walls of the bracket. These receiving apertures are spaced apart from each other in a longitudinal direction of the tube.
The tubular body is aligned until it rests against the profile shell and along a straight line between the lower region and an upper end. The lower region of the tubular body is positioned in the receiving apertures so that the tubular body can be attached to the bracket walls directly or indirectly. The straight line is inclined to a vertical line which essentially extends perpendicular to the walls of the bracket.
The tubular body is attached to the bracket and to the profile shell.